The present invention relates to a novel thin film magnetic head, a recording/reproduction separation type head using the thin film magnetic head, and a magnetic recording and reproducing apparatus.
A thin film magnetic head for a magnetic disk apparatus is formed on a slider held above a disk which rotates at high speed. The magnetic head has a magnet pole layer in the form of a thin film made of a ferromagnetic material. On an air bearing surface (ABS), a lower magnetic pole layer and an upper magnetic pole layer are provided on and under a gap layer. The upper and lower magnetic pole layers of the recording head are in contact with each other in the rear part of the gap. In order to increase the recording density, it is necessary to write a large amount of data on the surface of a magnetic disk. For this purpose, it has been proposed to narrow the track width, thereby increasing the recording density. A method which provides a thin film magnetic head having a width at the magnetic pole end, that is, a track width, of 2 .mu.m or narrower is described in Japanese Patent Application Laid-Open No. 7-296328 which corresponds to U.S. Pat. No. 5,652,687. According to the method described in this publication, when a magnetic film is formed by plating, a silicon dioxide layer is used as a plating frame. It is described in the publication that the magnetic pole layers from the ABS to the zero throat level in the rear part are wider than a magnetic pole end layer and are in parallel, and that a parallel path is formed for receiving and transferring the magnetic flux from/to the magnet pole end region, thereby enhancing the magnetic flux transmitting ability. Further, the shape of the upper magnetic film (shown by P2(T) in FIG. 24 and P2 in FIG. 25 corresponding to FIG. 20 and FIG. 21 of U.S. Pat. No. 5,652,687) is clearly shown in the head construction diagram of FIGS. 24 and 25 of the publication. The cross-sectional area of the upper magnetic film is constant, when it is seen from the air bearing surface at the gap depth position (upper part of the frame).
It is an object of the invention to provide a thin film magnetic head with less blur having a high recording magnetic field, and a recording/reproduction separation type magnetic head using the thin film magnetic head as well as a magnetic recording and reproducing apparatus.
It is another object of the invention to provide a high-frequency driven magnetic head having a magnetic pole width of 1 .mu.m or narrower and a magnetic recording and reproducing apparatus which uses the magnetic head and has a very high recording density.